The present invention relates to management of multiple generations of backup data.
In recent years, storage devices for storing large amounts of data have become widespread. A storage device of this kind is connected via a network to a number of information processing devices. In the storage device, backup is carried out so as to enable data to be restored in the event that a physical or logical failure has occurred in a volume storing data used for service. In many instances, such backup is carried out at predetermined periodic intervals (a backup cycle). Backup data is typically managed in multiple generations.
Ordinarily, there is a limit as to the number of backup volumes for storing backup data. Thus, when managing multiple generations of backup data, several volumes are rotated, and backup carried out while overwriting the new backup data onto volumes holding backup data that is no longer needed. Settings such as the number of generations of backup data to be managed and save period for which backup data should be saved, that is, the array of the period for which the administrator wishes to keep at least one backup data, are made by the administrator. Then, on the basis of the number of backup volumes, number of backup data generations, and the save periods, the administrator creates a backup schedule.
Various algorithms may be employed to create a backup schedule that involves backing up while rotating a number of volumes. Examples of such algorithms include the “round robin”, “GFS (Grandfather-Father-Son)” and “tower of Hanoi” algorithms. Also know is the technique taught in Japanese Patent Laid-Open Gazette No. 11-194964.
However, the algorithms mentioned above have the drawback that one save period is interrelated to the others such that if the save period is modified, it is necessary to simultaneously modify the other save periods, and this drawback makes it difficult for the administrator to set the save period on an individual basis. Especially, from the standpoint of efficient utilization of a limited number of backup volumes, it would be desirable to be able to set save periods on an individual basis.